Due to a lack of depth on the offensive line, Shirley switched from defensive tackle, the position he played for his first two NFL seasons, to offensive guard during 2009 training camp.[1] Shirley was waived by the Cincinnati Bengals on September 5, 2009. He was signed to a reserve/future contract on January 11, 2010. He was released on September 3, 2011.

Shirley signed on to the Carolina Panthers' practice squad on November 8, 2011.[2] Shirley was promoted from the practice squad on December 7, 2011. He played in the final four games for the Panthers, recording four tackles, 2.5 sacks, and one forced-fumble. [3]